IS15493:2004 Indian Standard GASEOUS FIRE EXTINGUISHING SYSTEMS -- GENERAL REQUIREMENTS ICS 13.220.10 0 BIS 2004 BUREAU OF INDIAN STANDARDS SHAH ZAFAR MARG MANAK BHAVAN, 9 BAHADUR NEW DELHI 110002 August 2004 Price Group 10 Fire Fighting Sectional Committee, CED 22 FOREWORD i'his Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized Fire Fighting Sectional Committee had been approved by the Civil Engineering Division Council. by the Attention is drawn to Montreal Protocol on substances that deplete the ozone layer. As India is a signatory to the Protocol. country programme was drafted wherein suitable alternative clean agents have been identified in the place of HaIons 1301 and 12 I 1. As per the approved programme, this standard has been formulated for the identified alternatives. The agents covered in this standard are thus introduced in response to international restrictions on the production of certain Halon fire extinguishing agents under the Protocol signed in 1992, as emended. [t is important that the fire protection of a building or plant be considered as a whole. Gaseous clean agent systems form only a part, though an important part, of the available facilities, but it should not be assumed that (heir adoption necessarily removes the need to consider supplementary measures, such as the provision of portable tire extinguishers or other mobile appliances for first aid or emergency use, or to deal with special hazards. Gaseous fire suppression systems covered in these Indian Standards are designed to provide a supply of gaseo~ls exting~lishillg mediuln for the extinction of fire invo]ving high value assets. Gaseous clean agents have for many years been a recognized effective medium for the extinction of flammable liquid fires and fires in the presence of electrical and ordinary Class A hazards, but it should not be forgotten, in the planning of comprehensive schemes, thatthere may be hazards for which these mediums are not suitable, or that in certain circumstances or situations there may be dangers in their use requiring special precautions. These difficulties have been addressed in this standard. Various methods of supplying clean agent to, and applying it at, the required point of discharge for fire extinction have been developed in recent years, and there is a need for dissemination of information on established systems and methods. This standard has been prepared to meet this need. New requirements to eliminate the need to release clean agents during testing and commissioning procedures are included. These are linked to the inclusion of enclosure integrity testing. The requirements of this Indian Standard are made in the light of the best technical data available at the time of drafting this standard but, since a wide field is, covered, it has been impracticable to consider every possible factor or circumstance that might affect implementation of the recommendations. It has been assumed in the preparation of this Indian Standard that the execution of its provisions is entrusted to people appropriately qualified and experienced in the specification, design, installation, testing, approval, inspection, operation and maintenance of systems and equipment, for whose guidance it has been prepared, and who can be expected to exercise a duty of care to avoid unnecessary release of clean agent. Specific requirements and advice on these matters can be obtained from the appropriate manufacturer of the clean agent or the extinguishing system. Information may also be sought from the appropriate fire authority, the health and safety authorities and insurers. In addition, reference should be made as necessary to other statutory regulations. It is essential that fire equipment be carefully maintained to ensure instant readiness when required. Routine maintenance is liable to be overlooked or given insufficient attention by the owner of the system. The importance of maintenance cannot be too highly emphasized. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated. expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 `Rules for rounding off numerical values (revised)'. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. 1S 15493:2004 Indian Standard GASEOUS FIRE EXTINGUISHING SYSTEMS -- GENERAL REQUIREMENTS 1 SCOPE This standard specifies provisions and recommendations for general requirements, type of clean agent and their containers, container arrangement, distribution systems, such as piping, nozzles, pipe supports, alarm system, type of enclosure etc. NOTES 1 This standard covers the general requirements applicable to totai tlooding clean agent systems like Halo-Carbon agents and inert gas agents. In addition, individual requirements for each type of clean agent system are covered un-der separate standards. Detailed design guidelines are specitied, in other standards. Hence before designing a protection with a particular clean agent, both the standards should be read together. Wherever there is a difference, the individual standard takes precedence, 2 This standard prescribes minimum requirements for total flooding clean agent tire/extinguishing systems. Protection with carbon dioxide is not covered in this standard. 3 Nothing in this standard is intended to restrict new technologies or alternate arrangements provided the level of safety prescribed by this standard is not diluted. responsible for approving installation or equipment or a procedure. 3.4 Automatic -- Performing a function without the necessity of human intervention. 3.5 Automatic/Manual Switch -- A means of converting the system from automatic to manual ( manual override) and vice-versa. 3.6 Class A Fires materials, such as plastics, electrical any flammable fiid -- Fire in ordinary combustible wood, cloth, paper, rubber, many and electronic hazards without or gas. 3.7 Class B Fires -- Fire in flammable liquids, oils, greases, tars, oil-based paints, lacquers and the like. 3.8 Clean Agent -- Electrically non-conducting, vaporizing, or gaseous clean agent that does not leave a residue upon evaporation. The word agent wherever appearing in this document shall mean as clean agent. 3.9 Clearance -- The air distance between clean agent equipment, including piping and nozzles and unenclosed or uninsulated live electrical components at other than ground potential. 3.1O Containers -- A cylinder or other vessels used to store the clean agent. 3.11 Container-Discharge Valve -- A valve directly connected to a container which when actuated releases the clean agent into the distribution piping. 3.12 Control Device -- A device to control the sequence of events leading to the release of clean agent. 3.13 Concentration 2 REFERENCES The standards listed in Annex A contain provisions which through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision and the parties to agreements based on this standard are encouraged to apply the most recent editions of the standards indicated in Aflnex A. 3 TERMINOLOGY For the purpose of this standard, definitions shall apply. the following 3.1 Adjusted Minimum Design Quantity ( AMDQ ) -- The minimum design quantity of agent that has been adjusted in consideration of design factors. 3.2 Approved -- Acceptable to a relevant authority. In determining the capability of the installations, the authorities may base their acceptance with appropriate standards. The design and system approval shall be from national or international approving authority or lab of repute. 3.3 Authority -- The organization, office or individual 1 3.13.1 Design Concentration -- The concentration ( including safety factor ) of the clean agent necessary to extinguish a fire of a particular fuel. .Extinguishing Concentration -- The 3.13.2 concentration ( without safety factor ) of the agent necessary to extinguish a flame ofa particular fuel at atmospheric pressure. 3.13.3 Hazardous Concentration concentration that exceeds the ( see 3.28) for the agent used. -- The LOAEL IS 15493:2004 3.13.4 Injected Concentration -- The concentration of the agent necessary to develop under free efflux conditions the required design concentration. 3.13.5 Maximum Concentration -- The concentration achieved from the actual clean agent quantity at the maximum ambient temperature. -- The 3.13.6 Residual Oxygen Concentration resulting concentration of oxygen achieved within a protected area after the discharge of agent into the area. extinguishing concentration surrounds the hazard. 3.24 Inert Gas Agent -- A clean agent that contains as primary components one or more of the gases IGOI,IG55, IG100or !G541. 3.25 Inerting -- The prevention of reignition of a flammable or explosive atmosphere by establishing a suitable concentration of the clean agent. 3.26 Liquefied Gas -- A gas or gas mixture ( normally a halocarbon ) which is liquid at the container pressurization level at room temperature ( 20°C ). 3.27 Lock-Off Valve -- A mechanically operated device which prevents a clean agent from being discharged through distribution pipe work to the protected area. 3.28 Lowest Observed Adverse Effect Level ( LOAEL ) -- The lowest concentration of clean agent at which an adverse toxicological or physiological effect has been observed. 3.29 Manual -- Requires a human intervention to accomplish a function or task. 3.30 Maximum Working Pre-ssure --Equilibrium pressure within a cylinder at the maximum working temperature. For liquefied gases, this is at maximum fill density and may include super-pressurization, if applicable. 3.31 Minimum Design Quantity ( MDQ ) -- The quantity of agent required to achieve the calculated minimum design concentration. 3.32 Monitoring -- The supervision of the operating integrity of an electrical, mechanical, pneumatic or hydraulic control feature of a system. 3.33 No Observed Adverse Effect Level ( NOAEL ) -- The highest concentration of a clean agent at which no adverse toxicological or physiological effect has been observed. 3.34 Non-liquefied Gas -- Gas or gas mixture which, under reserve pressure and allowable reserve temperature conditions, is always present in a gaseous form. 3.35 Normally Occupied Area -- An area where, under normal circumstances, humans are present. 3.36 Normally Unoccupied Area -- Area not occupied by people but may be occasionally entered for brief periods. 3.37 Nominal Size -- A numerical designation .of size which is common to all components in a piping system other than components designated by outside diameters or by thread size. It is a convenient round number for reference purposes and is only 2 3.14 Design Factor ( DF ) -- A fraction of the agent minimum design quantity ( MDQ ) added thereto deemed appropriate due to a specific feature of the protection application or design of the suppression system. 3.15 Directional Valve -- A device for controlling the passage of the clean agent from a supply manifold and directed to pre-selected area(s) of protection. 3.16 Discharge Inhibit Switch -- A manually operated switch that prevents the automatic discharge of the clean agent. 3.17 Distribution System -- All the pipe work and fittings downstream of any container discharge valve. 3.18 Engineered Systems -- A system in which the supply of the clean agent stored centrally is discharged through a system of pipe and nozzles in which the size of each section of pipe and nozzle orifice has been calculated in accordance with relevant clauses of ttiis standard. The design flow rates from nozzles may vary according to the design requirements of the hazard. 3.19 `Fill Density-- The mass of gaseous agent per unit volume of container ( kg/m3 ). 3.20 Final Design Quantity ( FDQ ) --A quantity of agent determined from the agent minimum design quantity as adjusted to account for design factors and pressure adjustment. 3.21 Flooding Quantity -- Mass or volume of clean agent required to achieve the design concentration within the protected volume within the specified discharge time. 3.22 Gross Volume -- The volume enclosed by the building elements around the protected enclosure, less the volume of any permanent impermeable building elements within the enclosure. 3.23 Holding Time -- Period of time during which a concentration of clean agent greater than the fire IS 15493:2004 loosely related to manufacturing dimensions. 3.38 Operating Device -- Any component involved between actuation and release mechanisms, 3.39 Pre-engineered Systems -- Those having pre-determined flow rates. nozzle pressures and quantities of clean agent. These systems have the specific pipe size, maximum and minimum pipe lengths, flexible hose specifications, number of titt~ngs and number and types of nozzles prescribed by a testing laboratory. 3.40 Primary Release -- Release of clean agent initiated by detection system or manual operation under normal operating conditions. 3.41 Release -- The opening of the cylinder and directional valves leading to the physical discharge or emission of clean agent into the enclosure. 3.42 Safety Factor ( SF ) -- A multiplier of the agent inerting flame extinguishing or concentration to determine the agent minimum design concentration. 3.43 Safety Interlock -- A switch that monitors the occupation of the protected area and automatically inhibits the discharge of the clean agent when the area is occupied. 3.44 Sea Level Equivalent of Agent -- The agent concentration ( volume, percent ) at sea level for which the partial pressure of agent matches the ambient partial pressure of agent at a given altitude. 3.45 Sea Level Equivalent of"Oxygen -- The oxygen concentration ( volume, percent ) at sea level for which the partial pressure of oxygen matches the ambient partial pressure of oxygen at a given altitude. 3.46 Secondary Release ( Slave) --A release that is a consequence and dependent on the operation of the primary release, for example, pneumatic connection. 3.47 Super-pressurization -- The addition of a gas to the clean agent container, where necessary, to achieve the required pressure for proper system operation. 3.48 Total Flooding -- The act and manner of discharging an agent for the purpose of achieving a specified minimum agent concentration throughout a hazard volume. 3.49 Total Flooding Systems -- A fire fighting system that is arranged to discharge cl,ean agent into an enclosed space to achieve the appropriate design concentration. 3 4 GENERAL INFORMATION REQUIREMENTS 4.1 General 4.1.1 Extinguishing agents that are used through physical or properties of specific parts of this standard. gases are thr.ee-dirnensional effectively to suppress fire chemical action. Separate gases are provided in other AND 4.1.2 Gaseous total flooding systems may be used to suppress fires of Classes A and B type as defined in 3.6 and 3.7. However, for suppressing fires where flammable gases may be present, the possibility of explosion, during and after system discharge should be considered. 4.1.3 Clean agent gas extinguishing systems are useful within the Iimits. of this standard in extinguishing fires in specific hazards or equipment and in occupancies where "an electrically nonconductive medium is essential or desirable, or where clean-up of other media poses a problem. 4.1.4 Where clean agent gas extinguish& systems are used, a fixed enclosure shall be provided about the hazard that is adequate to enable the specific concentration to be achieved and maintained for the =specified period of time. 4.1.5 The effects of agent decomposition on fire protection effectiveness shall be considered when using clean agents in hazards with high temperatures ( for example, furnaces and ovens, etc ). 4.1.6 The design, installation, service and maintenance of the gas extinguishing systems shall be performed by those competent in the respective field in accordance with IS 15496:2004. 4.1.7 The installer of the clean agent system shall be certified by a reputed national/international agency/laboratory and sLIch certification shall be valid at the time of installation. 4.2 Suitability and Application 4.2.1 Total Flooding Svstems Gaseous fire extinguishing systems are used primarily to protect hazards that are in enclosures or equipment that, in itself, includes an enclosure to contain the agent for establishment of required concentration and maintenance thereof for the required pwiod. Some typical hazards that may be suitable include, but or not limited to, the following: a) Within enclosures, such as rooms, vaults, enclosed machines, containers, storage tanks and bins; 1S 15493:2004 b) For enclosed electrical hazards, such as transformers, control cubicles, switch boards, circuit breakers, and rotating equipment; Forenclosed flammable liquid/gas storage and processing areas; For engines using tlammable fuels; For electronic hazards, such as computers, data processing equipment, control room, telecommunication facilities; Sub-floors and other concealed spaces; and Other high value assets. means other than the tire. 4.3.2 Electrostatic charging of non-grounded conductors may occur during the discharge of These gaseous fire extinguishing systems. conductors may discharge to other objects causing an electric arc of sufficient charge to initiate explosion in potentially explosive atmospheres. 4.4 Other Information 4.4.1 All devices in respect of the gaseous fire extinguishing systems shall be designed for the service they will encounter and shall not be readily rendered inoperative or susceptible to accidental operation. Normally, the system components shall be designed to function properly from ­ 210 to 55°C or marked to indicate temperature limitations in accordance with the specifications. 4.4.2 Gaseous fire extinguishing systems may be employed to protect more than one enclosure, if necessary, by means of directional valves. Where there are two or more enclosures simultaneously involved in a fire by reason of their proximity, such enclosures shall be protected by individual systems designed to allow simultaneous operation, or a single system sized and arranged to discharge on all potentially involved hazards simultaneously. 4.4.3 Systems employing simultaneous discharge of different agents to protect the same enclosure shall not be permitted. 4.5 Applicability of Clean Agents 4.5.1 The fire extinguishing clean agents addressed in the standard are electrically non-conducting and leave no residue upon evaporation. 4.5.2 Tables I and IA show the details of clean agents that are covered in this standard. While requirements that are common to all these agents are prescribed in this standard, individual requirements for each agent are covered under separate standards. c) d) e) t) g) 4.2.2 Some of the gaseous fire extinguishing systems may also be used for explosion prevention and suppression where flammable materials may collect in confined area. 4.3 Limitations 4.3.1 Gaseous fire extinguishing systems shall not be used on tires involving the following materials unless they are pre-evaluated for the purpose: a) Certain chemicals or mixture of chemicals, such as cellulose nitrate, gun powder, which are capable of rapid oxidation in the absence of air; Reactive metals, such as lithium, sodium, potassium, magnesium, titanium, zirconium, and plutonium; Metal hydrides or metal amides, some of which may react violently with some gaseous agents; Chemicals capable of undergoing autothermal decomposition, such as certain organic peroxides and hydrazine or; Mixtures containing oxidizing materials, such as sodium chlorate or sodium nitrate; and Environments where significant surface areas exist at temperatures greater than the breakdown temperature of the extinguishing agent and are heated by b) c) d) e) f) Table 1 Halocarbon Agents ( Clause 4.5.2 ) SI No. Clean Agent Formulae (2) CHC12CF~ CHC1F2 CHCIFCF3 ( Detoxified ) Chemical (3) Name Commercial Name (4) (1) i) Dichiorotritluoroethane ( HCFC- 123, 4.75 percent ) Chlorodifloromethane ( HCFC-22. 82 percent} Chlorotetrafluoroethane ( HCFC- 124, 9.5 percent ) Isoproponyl - 1-Illetllylcyclollcxtille ( 3.75 percent ) Heptatluoropropane HCFC Blend A ii) CF3CHFCFJ HFC-227ea 4 IS 15493:2004 Table IA Inert Gas Agents ( C/uuse 4.5.2 ) SI No. (1) i) ii) iii) iv) Clean Agent Formulae (2) Ar Nz Nz Ar Nz Ar Chemical (3) Argon ( 100 percent ) Nitrogen ( 100 percent ) Nitrogen ( 50 percent ) Argon ( 50 percent ) Nitrogen ( 52 percent ) Argon ( 40 percent ) Carbon dioxide ( 8 percent ) Name Commercial Name (4) lGO1 IG 100 ICi 55 [G 541 C02 4.5.3 As such, both these standards, that is, for general and individual requirements should be read Where together before designing a system. requirements in both the standards differ, standard covering individual requirements shall take precedence. 5 REQUIREMENTS OF PLANS REGARDING SUBM1SS1ON details of the contents, such as volume, pressure, nominal capacity in agent mass at standard conditions of temperatures and pressures; j) Descriptions k) of pipes and fittings indicating also their specifications, pressure ratings, etc; Descriptions of nozzles employed indicating their size, orifice area, type, angle, etc, and their locations; Descriptions of detectors employed indicating their locations, mounting, etc; Plans shall contain sufficient details to enable an evaluation of the protected enclosure(s) or local vis-a-vis the effectiveness of the protection(s) system. Details shall include the property involved in the hazard(s), location(s), the enclosure limits and isolation of the hazards and the exposure of the hazards. 5.1 Plans for submission to the authorities shall be drawn up in accordance with the following requirements: a) Plans for integrity of fittings shall be clear, contain all required details including scale and point of compass and shall be clearly dated; Name of the enterprise, detailed postal address; location and m) Electrical cabling and terminations; n) P) Bill of material and equipment schedule for each component proposed for the syste]n. Suppliers/manufacturer-s names, details of approvals, quantity, etc; Isometric drawings showing the agent distribution system indicating the lengths and diameters of each pipe segment, nodal reference, fittings including unions, reducers, orifices, strainers, nozzles, flow rates in all segments, equivalent orifice areas, etc; Plan view of the enclosures showing the entire agent piping system along with ceiling, floors, false floors, walls, partitions, pipe supports, agent containers, cabling, panels, detectors, etc; Details showing the pipe supports, agent container securement, etc; Location of ducts and similar devices, dampers, air handling systems, venting arrangements and their details with supporting calculations, etc; Schematic display of the operation of the system giving chmnologica] sequence of operations prior to the discharge of the agent into the protected enclosures; Schematic diagrams showing the location 0 b) c) d) r) Location and construction of the protected enclosures, walls and partitions; Cross and longitudinal sectional elevations of the protection enclosures showing the full height, schematic diagram, ceilings, false floors, etc; Type of clean agent proposed to be used; Concentration summary, that is, design, extinguishing, injected and inerting, etc: Type of the hazards proposed to be protected including descriptions of the occupancies, surroundings, wall/ceiling openings, etc; Location of the gas containers and 5 u) s) t) e) f) ~) h) v) IS 15493:2004 and layout of all the power and indicating equipment connections, control panels, annunciate panels, etc; w) Tables showing the calculations for enclosure volumes, agent quantity, methods used to determine number and location of audible and visual indicating equipment, number and location of detectors, etc; and Y) Other features like interconnection with other type of fire protection systems, etc, with the proposed system. 5.2 The details of the system shall include information and calculations on the amount of agent; container storage pressure; internal volume of the containers; the location, type and flow rate of each nozzle including equivalent orifice area; the location, size and equivalent lengths of pipe, fittings, siphon tube, valve, discharge head and flexible connector hose; and the location and size of the storage facility. Pipe size reductions and orientation of tees shall be clearly indicated. Details shall be available on location and function of the detection devices, operating devices, auxiliary equipment and electrical circuitry. All the apparatus, equipment used in the system shall be easily identifiable. 5.3 An as-built drawing shall be submitted upon completion of the installation for approval. Instruction and maintenance manuals that include a full sequence of operations and a full set of drawings and calculations shall be available on site. 5.4 Flow Calculations System flow calculations along with the working drawings shall be submitted to the authorities in advance for approval. The hydraulic calculations shall be performed using calculation method approved by the authorities. 6 SAFETY REQUIREM-ENTS 6.1 Safety Precautions ( for Personnel) b) In areas, where there is a likelihood of significant difference between gross and net volumes of the enclosure, utmost care shall be exercised in pnoper system design to ensure that maximum concentrations are not exceeded. 6.1.1 Safety Precautions a) Normally (for Protected Areas ) occupied area -- The minimum safety precautions taken shall be in accordance with Table 2A and provisions therein, and Normally unoccupied areas -- The maximum concentration shall not exceed the LOAEL for the agent used unless a lock-off valve is fitted. Warning -- Any change to the enclosure volume, or addition or removal of contents that was not covered in the original design will affect the concentration of agent. In such instances the system shall be re-calculated to ensure that the required design concentration is achieved and that the NOAEL or the LOAEL are not exceeded. 6.1.2 For unoccupiable areas, the maximum concentration may "exceed the LOAEL for the extinguishant used, without the need for a lockoff valve to be fitted. 6.1.3 Protection of Occupants In any use of the gaseous system, where there is a possibility that people may enter or have difficulty seeking egress from the protected enclosure, suitable safeguards shall be provided. Such safety aspects as personal training, warning signs, pre-discharge alarms and safety interlocks shall be provided. Means of proper ventilation after fire should be readily available. 6.2 Safety Precautions ( Total Flooding Systems) 6.2.1 In areas protected by total flooding systems, that are capable of being occupied, the provision of the following safety aspects shall apply: a) Mandatory requirements: The discharge of some of the gas agents in fire extinguishing concentrations creates serious hazards for personnel in both the protected area and the areas to which the gas may migrate and also to properties in the vicinity of agent discharge. These hazards may include reduced visibility, suffocation and toxicity, during and afterthe discharge period. The relevant information on the above is available in Annex B. The tox[city information on the gaseous fire agents is given in Table 2. More details are specified in other relevant standard. Where hazardous concentrations of agent may exist, Iock-offvalves shall be fitted to the system. 6 1) A time delay shall be provided for evacuation prior to agent discharge. The agent discharge delay time shall be based on an engineering assessment of egress time for occupants in the area protected, 2) Safety interlocks and lock-off valves shall be provided wherever required as per Table 2. 1S 15493:2004 Table2 Toxicity Information on Clean Agent Suppression Systems ) NOAEL LOAEL LC50 or ALC ( Percentage by Volume ) (4) 10 (5) >10 (6) 64 ( Clauses 6.1 and6.2.l S1 No. (1) i) Clean Agent (2) HCFC Blend A CHC12CF3 CHCIF2 ( CHC1FCF3 Detoxified Chemical (3) ( 4.75 percent ) 82 percent ) ( 9.5 percent ) (3.75 percent) Formula r ii) iii) HFC-227ea IG-541 CF2CHFCF3 Nitrogen ( 52 percent ) Argon ( 40 percent ) Carbon dioxide ( 8 percent ) Nitrogen ( 50 percent ) Argon ( 50 percent ) Nitrogen ( 100 percent ) Argon ( 100 percent ) 9 43 10.5 52 >80 Not applicable Not applicable Not applicable Not applicable iv) v) vi) IG-55 IG-1OO IG-01 43 43 43 52 52 52 Table 2A Minimum Safety Precautions ( Clauses 6.1.1 and%.2.l ) S1 No. Injected Agent Levels Requirements r Inhibit Switch and Time Delay (3) Required Required Required Egress in 30 s (4) Not required Required Not Applicable') Safety Interlock (5) Not required Required Required Lock-off' Valve (6) Not required Not required Required (1) i) ii) iii) (2) Up to NOAEL Above NOAEL and up to LOAEL Above LOAEL NOTE -- The-purpose of the table is to avoid unnecessary exposure ot'occupants to the agent discharged, Factors such as the time for egress and the risk to the occupants by the fire must be considered when determining the system discharge time delay. 1)con~ntration levels above LOAEL are-not permitted in occupied areas and question of egress does not ark. 3) Exit routes which shall be kept clear at all times and the provision of emergency lighting and adequate direction signs to minimize travel distances, Outward swinging self-closing doors which can be opened from inside including when locked from the outside, Continuous visual and audible aIarms at entrances and designated exits until the protected area has been made safe, Warning and instruction signs shall be arranged as per clause, Pre-discharge alarms within such areas that are distinctive from all other alarm signals and that will operate immediately upon detection of fire, 7 b) 8) 4) Means of prompt ventilation of such areas after any discharge of agent. Forced draft ventilation will often be necessary. Care shall be taken to completely dissipate hazardous atmospheres and not just move them to other locations, as agents are generally heavier than air, and instructions and drills of all personnel within or in the vicinity of protected areas, including maintenance and construction personnel who may be brought into the area, to ensure their correct actions when the system operates. requirements: 9) 5) 6) m Recommendatory 1) Adding an odour to the agent so that the hazardous atmospheres are recognizable, IS 15493:2004 2) 3) Self-contained breathing apparatus and personnel trained for its use, and Means to detect a hazardous atmosphere in or around the protected area. Discharge practicable, protection shall be extended to include the adjacent connected hazards or work areas; c) Particular attention should be given to openings around cable, duct and pipelines ( similar utility services ) penetrating through the wall(s) and floor(s); In case of unavoidable openings, such openings should be restricted to as minimum as possible; In such cases, quantity of agent need to be suitably increased in consultation with the authorities concerned for maintaining the the within desired concentration enclosure; In case of item (c) above, the openings should be effectively sealed or preferably fire studded; and Injecting more quantity of agent in most of the cases, will only increase the rate of loss of agent through such openings. Hence, openings in the wall(s) and floor(s) shall be kept only to optimum requirements with increase in quantity of agent as discussed in item (d) above. 6.2.2 Electrostatic To avoid a situation as stated in 4.3.2, the components of the inerting system, such as pipe work, etc, shall be bonded and earthed as per National Electrical Code( SP30 : 1985). 6.3 Miscellaneous Hazards d) e) Certain other types of hazards associated with the usage of gaseous systems are as under: a) Noise -- Discharge ofa gaseous system can cause a noise loud enough to be startling, but not enough to cause traumatic injury; b) Turbulence -- The turbulence caused by the high velocity discharge from nozzles may be sufficient to dislodge substantial objects directly in its path, such as ceiling tiles and light fittings. Therefore, tiles and light fittings should be properly anchored. System discharge may also cause enough general turbulence in the enclosure to move unsecured -paper and light objects; Elec~rical clearance -- Where exposed electrical conductors are present, all system components shall be located no less than the minimum clearances from the energized parts. The clearances stipulated in National Electrical Code shall be maintained for safe operating conditions. Where the design basic insulation level is not available and where nominal voltage is used for the design criteria the highest minimum clearance listed for the purpose shall be used; and f) g) 7.2 Air Handling System and Similar Services a) Humidification and air handling systems catering to the protected areas shall be capable of automatic shutdown prior to the agent discharge, Also dampers shall be available inside the systems to stop flow of agent through ducts and similar means and these shall close automatically prior to agent discharge; Where it is necessary for air handling systems to be kept operating to provide cooling arrangement for essential equipment, quantity of the agent shall need to be suitably increased to include the volumes of both air and the ventilation system in addition to the volume of protected enclosure in consultation with the authorities concerned for maintaining the desired concentration within the enclosure; The operations within the enclosure that are likely to di-sperse the discharge of the agent, such as pumps, spray guns, heaters, etc, shall not be left running during the discharge of the agent and suitable provisions shall be available to shut them down prior to agent discharge; and In case of extinguishment of deep-seated fires such as those involving solids. Unclosable openings shall be provided c) b) d) Other hazards, if any, appropriate to the selected gaseous agent as specified in the other clauses of this standard shall be given due attention. FOR THE PROTECTED 7 REQUIREM-ENTS ENCLOSURES 7.1 Unclosable Openings a) The protected enclosure shall have sufficient structural strength and integrity to contain the agent discharge; The area of the unclosable openings such as ventilator openings within the enclosure shall be kept to as least as possible to avoid ingress of the agent through the leakages to the adjoining areas. Where confinement of the agent within the enclosure is not 8 c) b) d) IS 15493:2004 only in the ceiling level and such openings near the walls and partitions shall be avoided. 8 COMPONENTS SYSTEMS OF GASEOUS FLOODING Explosives, Nagpur, Each agent container shall have a permanent nameplate or other permanent marking that indicate the details as per Table 4. A reliable means shall be provided to determine the pressure in refillable superpressurized containers, and Th~ agent containers connected to a common manifold shall conform as per the provisions in Table 5. Table 4 Marking on Storage Container [ Clause 8. 1.2(e) ] S1 No. (1) i) Clean Agent (2) Halocarbon clean Marking on Container (3) Name of the agent Tare and agents gross weights Super-pressurization level of the container Name of the agent Pressurization level of the container Nominal agent volume 8.1 Agent Supply and Container Arrangement 8.1.1 Agent Supply a) Quality Requirement -- The clean agent shall comply with quality and purity standards appr~priate to the agent selected for extinguishment. Each batch of agent manufactured shall be tested and certified to applicable specification. Agent blends shall remain homogeneous in storage and use within the approved temperature range and envirornnental conditions at the place of installation; b) Quantity Requirements ( Main ) ­ The amount of agent in the system shall be at least sufficient for the largest single hazard or group of hazards to be protected simultaneously; Quantity Requirements (Reserve) ­ Same quantity equivalent to the largest single hazard or group of hazards to be protected simultaneously shall be available as reserve. However, if the replenishing of agent supply takes more than 7 days at the site of installation, authority concerned may insist on more quantity to be kept available as reserve; and Uninterrupted Protection ii) inert gas clean agent c) Table 5 Arrangement of Containers with Common Manifold [ C/ause 8. 1.2(g) ] S1 No. (1) Clean Agent (2) Halocarbon clean agents Containers with Common Manifold (3) Agents in a multiple container system -- all containers supplying the same manifold outlet for distribution of the same agent shall be interchangeable, of same nominal size and ca~acitv. filled with same n;min;l mass of agent and pressurized to the same nominal working pressure Agents shall be permitted to utilize multiple storage container sizes connected to the common manifold provided the containers are all pressurized to the same nominal working pressure i) d) uninterrupted protection the main and reserve permanently connected piping and arranged for t?.1.2 Agent Storage a) -- Where is required, both supply shall be to the distribution easy change-over. Agent shall be stored in containers designed to hold that specific agent at ambient temperatures, Agent containers shall be charged to a fill density or super-pressurization level with range specified by the manufacturers, Agent storage temperatures shall not exceed 55°C or be less than­21 "C. External heating or cooling shall be employed to keep the temperature of the agent storage container within the above limits if situation warrants so, The agent containers used in the flooding systems shall be designed to meet the requirements of the Department of 9 ii) b) Inert gas clean agents c) 8.1.3 Storage Container Arrangement d) The arrangement of storage accessories shall be as follows: a) containers and Containers and accessories shall be located and arranged so that inspection testing, IS 15493:2004 recharging and other maintenance is facilitated, and interruption to protection is kept to a minimum; b) Containers should be located outside and as near as practical to the enclosure protected. Containers protecting a single risk can be located within the enclosure they serve, only if sited so as to minimize the risk of exposure to fire and explosion; Containers shall be located so as not to be subject to severe weather conditions or to mechanical, chemical or other damage. Where excessive climatic or mechanical exposures are expected, suitable guards or enclosures shall be provided; Containers shall be adequately mounted to allow free passage of air around the base and suitably supported to provide for convenient individual servicing or content weighing. There shall be enough space for a full on-site inspection of the base of the container; In manifold systems, non-return valves or other automatic means shall be provided to prevent a loss of agent and to ensure personnel safety if the system is operated when any containers are removed for maintenance; Containers brackets or devices integral with the container for attachment to structures shall be designed to cater for the maximum expected mass, vibration effects and shock loading, appropriate to the installation; Reserve containers, where provided, shall be permanently sited or arranged for easy changeover; and Storage containers are located in areas where their leakage could lead to a hazardous concentration, consideration shall be given to the installation of gas detectors or other means to provide warning on the onset of hazardous conditions. Arrangements b) 8.2.1 General a) Pipe network, fitting shall be of noncombustible construction having physical and chemical properties such that their integrity under stress can be predicted with reliability; In severely corrosive atmospheres, special 10 c) corrosion resistant materials shall be required for pipes, fittings or support brackets and steelwork; Before final assembly, pipes and fittings shall be inspected visually to ensure they are free of burrs, swelter and rust and that no foreign matter is inside and the full bore is clear. After assembly, the system shall"be thoroughly blown through with dry air or compressed gas. The pipe work shall be.free of particulate matter and oil residue before the installation of nozzles and discharge devices; A dirt trap consisting of a `tee' with a capped nipple at least 50 mm long should be installed at the end of each pipe run. Drain traps should also be necessary if there is a possibility ofa build-up of water; In systems where valve arrangements introduce sections of closed piping, such sections shall be equipped with the following: 1) Indication of agent trapped in piping; 2) 3) 0 Means for safe manual venting; and Automatic relief of excess prtssure, where required. c) d) d) e) e) 9 Pressure relief devices, which can include the selector valve, shall be fitted so that the discharge, in the event of operation, will not endanger the personnel; and In systems using pressure-operated container valves, automatic means shall be provided to vent any container leakage that could build up pressure in the pilot system and cause unwanted opening of the container valve. The means provided for pressure venting shall not prevent operation of the container valve. @ g) h) 8.2.2 Piping Network 8.2.2.1 The piping used in the installation conform to the following requirements: a) shall 8.2 Agent Distribution Cast iron or non-metallic pipes shall not be used anywhere; Where used, flexible pipes, tubing, or hoses including connections shall be of approved materials with adequate temperature and pressure ratings; and The thickness of the pipes shall be in accordance with the provisions laid down in IS 6631. The internal pressure used for this calculation shall not be less than the greater of either of the following values: c) b) IS 15493:2004 1) The normal charging pressure in the agent container at21°C. 2) 80 percent of the maximum pressure in the agent container at the maximum storage temperature of not less than 55°C using the maximum allowable fill density specified by the manufacturer, inapplicable. values shown in the tables are used with prior acceptance of the -authorities, the minimum design pressure for the piping -shall be adjusted to the maximum pressure in the agent container at maximum temperature, using the basic design criteria specified in items C(1) and c(2) above. 8.2,3 Pipe Fittings a) The sizes and dimensions of pipe fittings shall be in accordance with 1S 1239 ( Part 2 ). Fittings shall be capable to withstand minimum rated working pressure equal to or greater than the minimum working pressure specified in 8.2.2.1 (c) for the clean agent being used. For systems that use a pressure reducing device in the distribution piping, the fittings downstream the device shall have a minimum rated working pressure equal to or greater than the maximum anticipated pressure in the downstream piping; Clean Agent System Piping d) Pipe joints shall be either threaded, welded or flanged type only and other types of jointing shall not be allowed. In no case shall the value used, for the minimum piping design pressure, be less than that specified in Tables 6 and 7 for the conditions shown. For halocarbon agents Table 6 shall be used and for inert gas agents Table 7 shall be used. Where different fill densities, pressurization levels or higher storage temperatures other than the Table6 Minimum Design Working Pressure for Halocarbon ( Clause 8.2.2.1) S1 No. Clean Agent Agent Container Maximum Fill Density kg/m2 (3) Agent Container Charging Pressure at 21OC Agent Container Charging Pressure at 55°C Minimum Piping Design Pressure at 21°C kPa (1) i) (2) (4) 1 0341) 2 482]) 4 1371) 4 1371) 2 4821) HFC-227ea 992 1 152 1 120 900 900 ii) HCFCBlendA with nitrogen. kPa (5) 1 703 3585 4950 5860 3723 kPa (6) 1 365 2868 3958 4689 2979 I)SuPer.Pressurized Table 7 Minimum Design Working Pressure for Inert Gas Clean Agent System Piping ( Clause 8.2.2.1) S1 No. Clean Agent Agent Container Charging Pressure at 21°C Agent Container Charging Pressure at 55°C Minimum Design r Piping Upstream of Pressure Reducer kPa (5) 16341 14997 14997 19996 15318 20424 30633 16580 22311 Pressure at 21°C > Piping Downstream of Pressure Reducer kPa (6) 6723 6728 6895 6895 6550 6550 6550 6895 6895 kPa kPa (1) i) ii) iii) (2) IG-O I IG-541 IG-55 (3) 16341 20424 14997 19996 15521 20424 30636 16580 22311 (4) 18271 22778 17755 23671 17065 22753 34 130 iv) IG-100 19300 26014 11 IS 15493:2004 b) Cast iron fittings shall not be used All threads used in joints and fittings shall comply with relevant Indian Standards; Welding ofjoints shall comply with relevant Indian Standards; and. Where copper, stainless steel, or other suitable tubing is jointed with compression type fittings, manufacturers pressure and temperature ratings of the fittings shall not be exceeded. and Supports nozzles shall be such that: shall be 1) The design concentration achieved in all parts of the enclosure; 2) The discharge shall not unduly splash flammable liquids or create dust clouds that might extend the fire, create an explosion or otherwise adversely affect the occupants; The velocity of discharge shall not adversely affect the enclosure or its contents; The discharge nozzles shall be provided with frangible discs or blow-out caps where clogging by foreign materials is possible. These devices shall provide an unobstructed opening upon system operation and shall be arranged so they will not injure personnel; c) d) 3) 8.2.4 Pipe Installation a) 4) In the installation of pipe work, care shall be taken to avoid possible restrictions due to foreign matter, faulty fabrication or improper installation. Pipe ends shall be reamed after cutting, where required; Where there is a possibility of explosions, the piping shall be attached to supports that are least likely to be displaced; and The maximum distance between supports shall take into account the total mass of pipe and the agent used. Distance between supports is indicated in Table 8. b) c) 5) .Nozzle shall be suitable for the intended use and shall be approved for discharge characteristics. The discharge nozzle consists of the orifice and any associated horn, shield or baffle; 6) Nozzles shall be of adequate strength for use"with the expected working pressures, be able to resist nominal mechanical abuse, and be constructed to withstand expected temperatures without deformation; and Nozzle discharge orifice inserts shall be ofcorrosion-resistant material. c) In order to minimize the possibility of lifting or displacement of lightweight ceiling tiles, precautions shall be taken to securely anchor the tiles for a minimum distance of 1.5 m from each discharge nozzle. Table 8 Maximum Pipe Work Distances [ Clause 8.2.4(c)] S1 No. Nominal Diameter of Pipe mm (2) 6 10 15 20 25 32 40 50 65 80 100 125 150 200 Maximum Pipe Work Distance mm (3) 0.5 1 1.5 1.s 2.1 2.4 2.7 3.4 3.5 3.7 4.3 4.8 5.2 5.8 (1) i) ii) iii) iv) v) vi) vii) viii) ix) x) xi) xii) xiii) xiv) 9 DETECTION, ACTUATION, ALARM AND CONTROL SYSTEMS 9.1 General 9.1.1 Detection, actuation, alarm and control systems shall be installed, tested and maintained in accordance with 1S2189. 9.1.2 Automatic detection and automatic actuation shall be used. 9.2 Automatic Detection 8.2.5 Discharge a) Nozzles Nozzles, including nozzles directly attached to containers, shall be of approved type and located with the geometry of the enclosure under consideration. The type, number and placement of 12 b) 9.2.1 Automatic detection shall be by any approved method or device capable of detecting and indicating heat, flame, smoke, combustible vapours or any abnormal condition in the hazard, such as process trouble, that is likely to produce fiie. 1S 15493:2004 9.2.2 Adequate and reliable primary and 24 h minimum standby sources of energy shall be used to provide for operation of the detection, signaling, control and actuation requirements of the system, 9.2.3 When a new agent system is being installed in a space that has an existing detection system, an analysis shall be made of the detection devices to assure that the detection system is in good operating condition and will respond promptly to a fire situation. This analysis shall be done to assist in limiting the decomposition products from a suppression event. 9.3 Operating Devices control for activation shal I be located not more than 1.2 m above the floor. 9.3.8 Where gas pressure from the system or pilot containers is used as a means for releasing the remaining containers, the supply and discharge rate shall be designed for releasing all of the remaining containers. 9.3.9 All devices for shutting down supplementary equipment shall be considered integral part of the system and shall function with the system operation. 9.3.10 All manual operating devices identified as to the hazard they protect. 9.4 Control Equipment 9.4.1 Electric Control Equipment shall be 9.3.1 Operating devices shail include agent releasing devices or valves, discharge controls and shutdown equipment necessary for successful performance of the system. 9.3.2 Operation shall be by approved mechanical, electrical or pneumatic means, adequate and reliable source of energy shall be used. 9.3.3 All devices shall be designed for the service they will encounter and shall not readily be rendered inoperative or .iusceptible to accidental operation. Devices normally shall be designed to function properly from ­2OOto 55°C or marked to indicate temperature limitations. NOTE -- Also care shall be taken to thoroughly evaluate and correct any factors that could result in unwanted discharge. The control equipment shall supervise the actuating devices and associated wiring and, as required, cause actuation. The control equipment shall be specifically listed for the number and type of actuating devices utilized and their compatibility shall have been approved. 9.4.2 Pneumatic Control Equipment 9.3.4 All devices shall be located, installed or suitably protected so that they are not subject to mechanical, chemical or other damage that would render them inoperative. 9.3.5 A mean of manual release of the system shall be provided. Manual release shall be accomplished by a mechanical manual release or by an electrical manual release when the control equipment monitors the battery voltage level of the standby battery supply and will provide a low battery signal. The release shall cause simultaneous operation of automatically operated valves controlling agent release and distribution. 9.3.6 The normal manual control(s) for actuation shall be located for easy accessibility at all times, including at the time of a fire. The manual control(s) shall be of distinct appearance and clearly recognizable for the purpose intended. Operation of any control shall cause the complete system to operate in its normal fashion. 9.3.7 Manual controls shall not require a pull of more than 18.1 kg ( 178 N ) nor a movement of more than 355 mm to secure operation. At least one manual 13 Where pneumatic control equipment is used, the lines shall be protected against crimping and mechanical damage. Where installations could be exposed to conditions that could lead to loss of integrity of the pneumatic lines, special precautions shall be taken to ensure that no loss of integrity will occur. The control equipment shall be specifically listed for the number and type of actuating devices utilized and their compatibility shall have been approved. 9.5 Operating Alarms and Indicators 9.5.1 Alarms or indicators or both shall be used to indicate the operation of the system, hazards to personnel, or failure of any supervised device. The type ( audible, visual or olfactory ), number, and location of the devices shall be such that their purpose is satisfactorily accomplished. The extent and type of alarms or indicator equipment or both shall be approved. 9.5.2 Audible and visual pre-discharge alarms shall be provided within the protected area to give positive warning of impending discharge. The operation of the warning devices shall be continued after agent discharge until positive action has been taken to acknowledge the alarm and proceed with appropriate action. 9.5.3 Abort switches generally are not recommended, however, where provided, the abort IS 15493:2004 switches shall be located within the protected area and shall be located near the means of egress from the area. An abort switch shall not be operated unless the cause for the condition is known and corrective action can be taken. The abort switch shall be of a type that requires constant manual pressure to cause abort. The abort switch shall not be of a type that would allow the system to be left in an aborted mode without someone present. In all cases the normal and manual emergency control shall override the abort function. Operation of the abort function shall result in both audible and distinct visual indication of system impairment. The abort switch shall be clearly recognizable for the purpose intended. 9.5.4 Alarms indicating failure of supervised devices or equipment shall give prompt and positive indication of any failure and shall be distinctive from alarms indicating operation or hazardous conditions. 9.5.5 Warning and instruction signs at entrances to and inside protected areas shall be provided. 9.5.6 Indication lamps shall be provided to indicate the status of the abort switch, that is, Green colour for `Auto', Yellow colour for the `Manual' and Red colour for `Discharge' modes. 9.6 Time Delays 9.6.1 For clean agent extinguishing systems, a pre-discharge alarm and time delay, sufficient to allow personn-el evacuation prior to discharge, shall be provided. For hazard areas subject to fast growth fires, where the provision of a time delay would seriously increase the threat to life and property, a time delay shall be permitted to be eliminated. 9.6.2 Time delays shall be used only for personnel evacuation or to prepare the hazard area for discharge. 9.6.3 Time delays shall not be used as a means of confirming operation of a detection device before automatic actuation occurs. 10 COMMISSIONING AND ACCEPTANCE To determine that the system has been properly installed and will function as specified, the tests specified in 10.2.2 to 10.2.9 shall be performed. 10.2 Review of Mechanical Components 10.2.1 The piping distribution system shali be inspected to determine that it is in compliance with the design and installation documents. 10.2.2 Nozzles and pipe size and, if appropriate, pressure-reducing devices, shall be in accordance with system drawings. The means for pipe size reduction and attitudes of tees shall be checked for conformance to the design. 10.2,3 Piping joints, discharge nozzles and piping supports shall be securely fastened to prevent unacceptable vertical or lateral movement during discharge. Discharge nozzles shall be installed in such a manner that piping cannot become detached during discharge. 10.2.4 During assembly, the piping distribution system shall be inspected internally to detect the possibility of any oil or particulate matter which could soil the hazard area or affect the agent distribution due to a reduction in the effective nozzle orifice area. 10.2.5 The discharge nozzles shall be oriented in such a manner that optimum agent dispersal can be effected. 10.2.6 [f nozzle deflectors are installed, they shall be positioned to obtain the maximum benefit. 10.2.7 The discharge nozzles, piping and mounting brackets shall be installed in such a manner that they will not potentially cause injury to personnel, Agent shall not directly impinge on areas where personnel may be found in the normal work area, or on any loose objects or shelves, cabinet tops, or similar surfaces where loose objects could be present and become -:".:1-. Illlssllcs. 10.2,8 All agent storage containers shall be properly located in accordance with `approved for construction' set of system drawings. 10.2.9 All containers and mounting brackets shall be securely fastened in accordance with the manufacturer's requirements. 10.2.10 An adequate quantity of agent to produce the desired specified concentration shall be provided. The actual enclosure volumes shall be checked against those indicated on the system drawings to ensure the proper quantity of agent. Fan rundown and damper closure time shall be taken into consideration. 14 The minimum requirements for the commissioning and acceptance of the gaseous extinguishing system shall be as follows. 10.1 General The completed system shall be reviewed and tested by a competent person to meet the approval of the authority. Only equipment and devices designed to national standards shall be used in the systems. IS 15493:2004 10.2.11 Unless the total piping contains not more than one change in direction fitting between the storage container and the discharge nozzle, and unless all piping has been physically checked for tightness, the following tests shall be carried out: a) All open ended piping shall be pneumatically tested in a closed circuit for a period of 10 min at 3 bar. At the end of 10 rein, the pressure drop shall not exceed 20 percent of the test pressure, and All closed-section pipe work shall be hydrostatically tested `to a minimum of 1.5 times the maximum working pressure for 2 min during which there shall be no leakage. On completion of the test, the pipe work shall b~purged to remove moisture. signaling, control and actuation requirements of the system. 10.3.4 All auxiliary functions ( such as alarm sounding or displaying devices, remote annunciators, air handling shutdown, power shutdown, etc ) shall be checked for proper operation in accordance with system requirements and design specifications. Alarm devices shall be installed so that they are audible and visible under normal operating and environmental conditions. Where possible, all air handling and power cut-off controls should be of the type that once interrupted require manual restart to restore power. 10.3.5 Check that for systems using alarm silencing, this function does not affect other auxiliary functions, such as air handling or power cut-off where they are required in the design specification. 10.3.6 Check the detection devices to ensure that the types and locations are as specified in the system drawings and are in accordance with the manufacturer's requirements. 10.3.7 Check that manual release devices are properly installed, and are readily accessible, accurately identified and properly protected to prevent damage. 10.3.8 Check that manual release devices used to release agents require two separate and distinct actions for operation. They shall be properly identified. Particular care shall be taken where manual release devices for more than one system are in close proximity and could be confused or the wrong system actuated. Manual release devices in this instance shall be clearly identified as to -which hazard enclosure they protect. 10.3.9 Check that for systems with a main/reserve capability, the main/reserve switch is properly installed, readily accessible and clearly identified. 10.3.10 Check that for systems using inhibit switches requiring constant manual force, these are properly installed, readily accessible within the hazard area and clearly identified. 10.3.11 Check that the control panel is properly installed and readily accessible. 10.4 Preliminary Functional Tests b) It is recommended that hydrostatic testing be carried out at the manufacturer's works where practicable. WARNING -- Pneumatic pressure testing creates a potential risk of injury to personnel in the area, as a result of airborne projectiles if rupture of the piping system occurs. Prior to conducting the pneumatic pressure test, the protected area shall be evacuated and appropriate safeguards shall be provided for test personnel. 10.2.12 A test using nitrogen, or a suitable alternative, shall be performed on the piping network to verify that flow is continuous and that the piping and nozzles are unobstructed. 10.2.13 Where required, suitable venting facilities shall be provided for the release of excessive pressure build-up during discharge of the agent. Individual standards for gaseous agents provide details for the design of venting facilities. 10.3 Review of Electrical Components 10.3.1 All wiring systems shall be properly installed in compliance with the appropriate National Standard and the system drawings..a,c. and d.c. wiring shall not be combined in a common conduit unless properly shielded and grounded. 10.3.2 All field circuitry shall be tested for ground fault and short circuit condition. When testing field circuitry, all electronic components ( such as smoke and flame detectors or special electronic equipment for other detectors, or their mounting bases ) shall be removed and jumpers properly installed to prevent the possibility of damage within these devices. Replace components after testing the circuits. 10.3.3 Adequate and reliable primary standby sources of energy which comply with 9.2.2 shall be used to provide for operation of the detection, 15 10.4.1 Where a system is connected to a remote central alarm station, notify the station that the fire system test is to be conducted and that an emergency response by the fire departmen(or alarm station personnel is not required. Notify all concerned personnel at the end-user's facility that a test is to IS 15493:2004 be conducted and instruct them as to the sequence of operation. 10.4.2 Disable or remove each agent storage container release mechanism and selector valve, where fitted, so that activation of the release circuit will not release agent. Reconnect-the release circuit with a functional device in lieu of each agent storage container release mechanism. For electrically actuated release mechanisms, these devices may include suitable lamps, flash bulbs or circuit breakers. Pneumatically actuated release mechanisms may include pressure gauges, Refer to the manufacturer's recommendations in all cases. 10.4.3 Check each resetable detector for proper response. 10.4.4 Check that polarity has been observed on all polarized alarm devices and auxiliary relays. 10.4.5 Check that all required end-or-line devices have been installed. 10.4.6 Check all supervised circuits for correct fault response. 10.5 System Functional Operational Test 10.6.2 Operate each type of alarm condition and verify receipt of fault condition at the remote station. 10.7 Control Panel Primary Power Source 10.7.1 Verify that the control panel is connected to a dedicated unstitched circuit and is labelled properly. This panel shall be readily accessible but access shall be restricted to authorized personnel only. 10.7.2 Test a primary power failure in accordance with the manufacturer's specification, with the system fully operated on standby power. 10.8 Review ofEnclosure-integrity It is preferable to subject all total flooding systems to an Enclosure Integrity ~est in order to detect and seal the significant leakage paths that could result in-failure of an enclosure to withhold design concentration for a specified period ( see 7,1 and 10.10 ). 10.9 Completion of Functional Tests When all functional tests are complete ( see `10.6 to 10.9 ), reconnect each storage container so that activation of the release circuit will release the agent. Return the system to its fully operational design condition. Notify the central alarm station and all concerned personnel at the end-user's facility that the fire system test is complete and that the system has been returned to full service condition by following the procedures specified in the manufacturers' specifications. 10.10 The complete installation shall be tested in one of the two methods narrated below: a) b) 10.5.4 switch. design audible panel. Where appropriate, operate the inhibit Verify that functions occur according to the specifications. Confirm that visual and supervisory signals are received at the control Full-scale discharge test, and Enclosure integrity test. 10.5.1 Operate the detection initiating circuit(s). All alarm functions shall occur according to the design specification. 10.5.2 Operate the necessary circuit to initiate a second alarm circuit if present. Verify that all second alarm functions occur according to design specifications. 10.5.3 Operate the manual release device. Verify that manual release functions occur according to design specifications. 10.5.5 Check the function of all resettable valves and activators, unless testing the valve will rele~se agent. `one-shot' valves, such as those incorporating frangible discs, should not be tested, 10.6 Remote Applicable ) Monitoring Operations ( If 10.6.1 Disconnect the primary power supply, then operate one of each type of input device while on standby power. Verify that an alarm signal is received at the remote panel after the device is operated. Reconnect the primary power supply. 16 Where the authorities concerned insist on full-scale discharge test, the test shall be conducted in accordance with various provisions under Annex C and results of the test ( that is concentration achieve-d, discharge time, holding time ) shall conform to various provisions available in other clean agent standards with particular reference to the agent used. Otherwise, the enclosure where total flooding system is installed, shall be subject to' enclosure integrity test' in accordance with various provisions under Annex D to demonstrate the retention time ( of the required concentration with the-enclosure ] as specified in other standards with particular reference to the agent used. 10.11 Completion Certificate and Documentation The installer shall provide to the user a completion IS 15493:2004 certificate, a complete set of instructions, calculations and drawings showing the system as-installed, and a statement that the system complies with all the appropriate requirements of this standard, and giving details of any departure from appropriate recommendations. The certificate shall give the design concentrations and, if carried out, reports of any additional test including the door fan test. 11 SYSTEM HYDRAULIC CALCULATIONS 11.1 General System flow calculations shall be carried out at a nolninal agent storage temperature of 21 "C, shall have been validated by an accredited approval authority by appropriate tests as described in this standard, and shall be properly identified. The system design shall be within the manufacturer's specified limitations. NOTES 1 Variations temperature calculations. from the nominal 21 "C storage will affect flow conditions used in NOTE -- These equations use friction factors and constants dependent on pressure and density obtained empirically. As the equations cannot be solved directly, a cornputcr programme is usually used to assist with the large number of iterative calculations in which pipe and nozzle sizes and if appropriate, size of pressure reducing devices, are selected within prescribedpressurelosses. 11.5 Valves and Fitting Valves and fittings shall be rated for resistance coefficient or equivalent length in terms of pipe, or tubing sizes with which they will be used. The equivalent length of the cylinder valves shall be listed and shall include siphon tube ( where fitted ), valve, discharge head and flexible connector. FLOW 11.6 Piping Length The piping length and nozzle and fitting orientation shall be in accordance with the manufacturer's approved manual to ensure proper system performance. 11.7 Drawings If the final installation varies from the prepared drawings and calculations new `as- built' drawings and calculations shall be prepared. 11.8 Liquefied Gases ( Specific Requirements) 2 Prc-engineered systems do not require a flow calculation when used within approved limitations. 11.2 Balanced 11.2.1 and Unbalanced System A balanced system shall be one in which: each actual or equivalent pipe length from the container to each nozzle are all within 10 percent of each other, and the discharge rate of each nozzle is equal. a) 11.8.1 Allowance shall be made for changes in elevation as specified in the relevant standard relating to the specific agent. 11.8.2 Minimum discharge rate for liquefied agents shall be sufficient to maintain the velocity required for turbulent flow to prevent separation. NOTE-- 11'turbuleat flow is not maintained, separation of the liquid and-gaseous phases will occur, which can lead to unpredictable tlow characteristics. 11.8.3 For information on two-phase flow for liquefied halocarbon gases ( see Annex E ). b) 11.2.2 Any system that does not meet the criteria mentioned in 11.2 shall be considered to be an unbalanced system. 11.3 Friction Losses Allowance shall be made for the friction losses in pipes and in container valves, dip tubes, flexible connectors, selector valves, time delay devices and other equipment ( for example, pressurereducing devices ) within the flow line. NOTE -- The flow of a liquefied gas will be a two phase phenomenon, the fluid consisting of a mixture of liquid and vapour, the proportions of which are dependent on pressure and temperature. The pressure drop is non-linear, with an increasing rate of pressure loss as the line pressure reduces by pipe friction. 11.4 12 ENGINEERED SYSTEM 12.1 General AND PRE-ENGINEERED All agents are suitable for use in both engineered central storage, system and pre-engineered ( modular or packaged ) systems, as described in 12.2 and 12.3. 12.2 Engineered Pressure Drop An engineered system uses large storage containers installed in central location. The containers are manifold together and a single pipe feeds the nozzle located inside the 17 The pressure drop shall be calculated using two phase flow equations for liquefied gases and single phase Now-equations for non-liquefied gases. IS 1-5493:2004 hazard area. Predicting pipe pressure losses and designing nozzle orifice sizes required complex flow calculations for both agent and nitrogen phases .( in case of halocarbon gases ) and for agent ( in case of line gases ), which takes into account the minimum and maximum volumes or the enclosure. 12.3 Pre-engineered A pre-engineered system involves a single container the maximum of two nozzles and a small piping network. This system can be multiplied to cover larger volume areas. The larger area is viewed as a number of smaller areas each protected by a single modular unit. 13 PHYSICAL PROPERTIES Physical properties of inert gas and halocarbon agents are shown in the Tables 9 and 10. 14 TRAINING 14.1 All persons who may be expected to operate, maintain, test or inspect fire extinguishing systems shall be kept continuously and adequately trained in the functions they are expected to perform. 14.2 Personal working in an enclosure protected by or gaseous extinguishant shall be trained and kept fully conversant with the operation and use of the system, particularly regarding safety requirements. Table 9 Physical Properties of Inert Gas Agents ( Clause 13 ) S1 No. (1) i) ii) iii) iv) v) vi) Properties (2) Molecularweight Boiling point at 760 mm Hg Freezing point Critical temperature Units (3) N/A T T T kPa Kj/kg"C IG-01 (4) 39.9 -189.85 -189.85 -122.3 4903 0.519 IG-1OO (5) 28.0 -195.8 -210.0 -146.9 3399 I .04 IG-541 (6) 34.0 -196 ­78.5 NIA NIA 0.574 IG-55 (7) 33.95 -190.1 ­199.7 -134.7 4150 0.782 Critical pressure Specific heat, vapour at constant pressure ( 1 atm ) and 25°C Heat of vaporization boiling point at vii) viii) Kj/kg TWA 163 1.01 199 I .0 220 1.03 181 1.01 Relative dielectric strength at 1 atm at 734 mm Hg, 25°C (N2 = 1.0) Volubility of water in agent at 25°C ix) NIA 0:006 percent 0.oo1 3 percent 0.015 percent 0.006 percent 18 IS 15493:2004 Table 10 -Physical Properties of Clean Halocarbon ( C/ause I 3 ) S1 No< (1) O ii) iii) iv) v) vi) vii) viii) ix) x) xi) xii) xiii) xiv) Molecular weight Boiling point at 760 mm Hg Freezing point Critical temperature Properties (2) Units (3) HCFC Blend A (4) 92.90 -38.3 <107.2 124.4 6647 162 577 1,~56 0.67 225.6 0,0900 0.21 1.32 0. I 2 percent by weight HFC 227ea (5) 170.03 -16.4 -[31 -101.7 2912 274 621 1.184 0.808 132.6 0.069 0.184 2.00 0.006 percent by weight Agents N/A "c "c "c kPa Cchnole kglms Kj/kg°C pressure point Kj/kg "C Kjlkg Critical pressure Critical volume Critical density Specific heat, liquid at 25°C Specific heat vapour at constant ( 1 atm ) and 25°C Heat of at 25°C vaporization at boiling Thermal conductivity of liquid at 25°C Whll"c Centipoises N/A Viscosity, liquid at 25°C Relative dielectric strength at 734 mm Hg, 25°C ( Nz = 1.0 ) I atm at Volubility of water in agent at 210C Pp m ANNEX A ( Clause 2 ) LIST OF REFERRED IS No. 1239 (Part2 ): 1992 Title INDIAN STANDARDS IS No. Title Mild steel tubes, tubtrlars and other wrought steel fittings: Part 2 Mild steel tubulars and other wrought steel pipe fittings (fourth revision ) Selection, installation and maintenance of automatic fire detection and alarm system -- Code of practice 6631:1972 Specification for steel pipes for hydraulic purposes National Electrical Code Inspection and'maintenance of fire gaseous extinguishing systems -- Code of practice SP 30:1985 15496:2004 2189:1999 19 ANNEX B 6.1 ) PRODUCTS (Clause INFORMATION ON SAFETY TO PERSONNEL AND DECOMPOSITION OF COMBUSTION II-l Any hazard to personnel created by the discharge of gaseous extinguishants shall be considered in the design of the system, in particular with reference to the hazards associated with particular extinguishants in the other standards of clean agents. Unnecessary exposure to all gaseous extinguishants shall be avoided. B-2 The decomposition products generated by tbe clean agent breaking down in the presence of very high amounts of heat can be hazardous. All of the present halocarbon agents contain fluorine. In the presence of available hydrogen ( from water vapour, or the combustion process itself ), the main decomposition product is hydrogen fluoride ( HF ). B-3 These decomposition products have a sharp, acrid odour, even in minute concentrations of only a few parts per million. This characteristic provides a built-in warning system for the agent, but at the same time creates a noxious, irritating atmosphere for those who must enter the hazard following a fire. B-4 The amount of agent that can be expected to decompose in extinguishing a fire depends .to a large extent on the size of the fire, the particular clean agent, the concentration of the agent, and the length of time the agent is in contact with the flame or heated surface. If there is a very rapid build-up of concentration to the critical value, then the fire will be extinguished quickly and the decomposition will be limited to the minimum possible with that agent. Should that agent's specific composition be such that it could generate large quantities of decomposition products, and the time to achieve the critical value is lengthy, then the quantity of decomposition products can be quite great. The actual concentration of the decomposition products then depends on the volume of the room in which the fire was burning and on the degree of mixing and ventilation. B-5 Although the vapour from halocarbon gas has low toxicity, the decomposition products can be very hazardous. The most widely accepted theory is that the vapour must decompose before the agent can inhibit the combustion reaction. Decomposition takes place on exposure to a flame or to a hot surface at a temperature above 480°.C. In the presence of available hydrogen ( from water vapour or the combustion process itself), the main decomposition product is hydrogen fluoride ( HF ). B-6 The decomposition products .of halocarb.on agents have a characteristic sharp acrid adour, even in minute concentrations of only a few parts per million. This characteristic provides abuilt-in warning system for the extinguishant, but at the same time creates a noxious, irritating atmosphere for those who have to enter the enclosure following a fire. The actual concentration of the decomposition products depends on the volume of the enclosure in which fire is burning and the degree of mixing and ventilation. B-7 Longer exposure of the vapour to temperatures in excess of 482°C would produce greater concentrations of these gases. The type and sensitivity of detection, cwpled with the rate of discharge, should be selected to minimize the exposure time of the vapours to the elevated temperature if the concentration of breakdown products is to be minimized. In most cases, the area would be untenable for human occupancy due to the heat and breakdown products of the fire itself. B-8 Clearly, longer exposure of the agent to high temperatures would produce greater concentrations of these gases. The type and sensitivity of detection, coupled with the rate of discharge, should be selected to minimize the exposure time of the agent to the elevated temperature if the concentration of the breakdown products is to be minimized. B-9 Non-liquefied agents do not decompose measurably in extinguishing a fire. As such, toxic or corrosive decomposition products are not found. However, breakdown products of the fire like carbon monoxide itself can still be substantial and could make the area untenable for human occupancy. 20 IS 15493:2004 ANNEX C (-Clause 10.10 ) REQUIREMENTS C-1 SCOPE This clause sets out a procedure to determine compliance of the gaseous total flooding system with the requirements for discharge time, concentration and holding time. C-2 PRINCIPLE The system is operated, discharge time is measured and concentration readings are taken at a specified height at nominated periods. C-3 TEST MEDIUM The test medium shall be the concerned halocarbon or inert gas. C-4 APPARATUS The following apparatus is required: a) A chart recorder type concentration meter calibrated in strict accordance with the manufacturer's instructions, A suitable time-measuring device, and Temperature-measuring equipment. g) h) e) f) d) 4) FOR FULL-SCALE DISCHARGE TEST required by the appropriate authority, and Where the geometry of the enclosure does not lend itself to sampling in the above manner, take a minimum of three samples at locations agreed upon by the appropriate authority. Set the continuous chart recorder type concentration meter for the agent concerned and check that the meter is calibrated in accordance with the manufacturer's instructions so that it will record concentration levels at each sampling point for 10 min from commencement of discharge, Record temperature in enclosure, Ensure that plant which is capable of affecting system performan-ce, for example, air-hand(ing plant is in its normal operating mode, Activate the system and record the discharge time ( see 11 ), and Record concentration readings and holding times ( see 11 ). b) c) C-5 PROCEDURE The procedure shall be as follows: a) Ensure that the preliminary checks, in accordance with respective standard pertaining to gaseous fire extinguishing system have been completed, Electrically isolate all flooding serving adjacent enclosures, systems a) C-6 RECOMMISS1ONING Restore all systems to a fully operational status. C-7 REPORTING The following shall be reported: 1) installation, designer and contractor; 2) 3) 4) 5) b) c) d) enclosure identification; enclosure temperature prior to discharge; design concentration; and position of sampling points. b) c) 1) Concentration measurements should be made at a minimum of three points, one-at the highest hazard level, 2) Locate sampling points in the enclosure at the specified heights ( see 10 ). Do not locate sampling points nearer than 200 mm to ceiling unless the combustibles being protected extend within that area, in which case special design considerations may be necessary, If more than one space or compartment is being simultaneously protected, locate a sampling point in each space in accordance with the above criteria. Additional sampling points may be Date and time of test, Discharge time, Concentraticms at each sampling point at I and 10 min from the commencement of discharge, and System deficiencies. 3) e) Cross-check various observed parameters with the respective operating clauses are in conformity therewith. 21 1S 15493:2004 ANNEX D ( Clause 10.10) REQUIREMENTS FOR TESTING ENCLOSURE INTEGRITY e) o D-1 TEST FOR DETERMINATION OF PREDICTED MINIMUM HOLD TIME D-1.1 Principle A fan is temporarily located within an access opening to pressurize and repressurize the enclosure, A series of pressure and air flow measurements is made from which the leakage characteristics of the enclosure; are established. The predicted hold time is calculated using these leakage characteristics on the following assumptions: a) That leakage occurs under the worst conditions, that is, when one-half of the effective leakage area is at the maximum enclosure height and represents the inward leakage of air, and the other half ( the lower leakage area ) of the total effective leakage area is at the lowest point in the enclosure and represents the outward leakage afextinguishant/air, That all leak flow is one-dimensional, ignoring stream functions, i.e. Two thermometers, temperatures, and to measure ambient Signs, reading "DO NOT OPEN -- PRESSURE TEST IN PROGRESS" and "DO NOT CLOSE -- PRESSURE TEST IN PROGRESS". NOTE -- Additional apparatus, such as measuring tapes, torches, ladders. tools to remove floor and ceiling tiles, computer or other calculating device, may be necessary. D-1.3 Calibration of Apparatus Fan Unit -- Calibrate the fan unit at the a) intervals and by the method recommended by the manufacturer. Keep records and, where appropriate, calibration certificates. Use a flow meter accurate to + 5 percent and a pressure-measuring device accurate to+ 1 Pa. b) Devices -- The pressure-measuringdevices shall be calibrated not more than 12 months before a test. Records shall be maintained and, where appropriate, calibration certificates. Press ure-Measttring b) c) That flow through any particular leak area is either into or out of the enclosure and either from or into an infinitely large space, That the system is at sea-level, at a temperature of 20"C, and atmospheric pressure of 1.013 bar absolute, and An enclosure integrity test is deemed successful when at least 80 percent of the design concentration is available within the enclosure at the expiry of 10 min (see D-2.10). If inclined manometers are used, change the fluid not more than 3 mcrnths before the test. Level and zero inclined manometers before each test, D-1.4 Preliminary a) Preparation d) e) Obtain a description from the user of the air-handling equipment and extinguishantextraction systems in the enclosure, Check for the following: 1) raised platform floors and false ceiling spaces; 2) 3) visually obvious leaks in the enclosure; adequate return paths outside the enclosure between all leaks and the"fan unit; and conflicting activities in and around the enclosure. b) D-1.2 Apparatus a) Fan unit, consisting of a frame which will fit into and seal an access opening in the enclosure, and one or more variable speed fans, with low flow facilities, capable of giving a differential pressure of not less than 25 Pa across the enclosure boundary, Two pressure-measuring devices, one to measure enclosure differential pressure and one to measure fan flow pressure, Flexible tubing, pressure-measuring Chemical generator, for connecting devices, and/or the smoke LL 4) c) Provide the following information to the user: 1) a description of the test; 2) the timerequired to complete the test; .3) what assistance will be needed from the user's staffl and 4) Information on any necessary disturbance to the building or its services during the test ( for example, b) c) d) smoke pencils IS 15493:2004 removal of floor or ceiling tiles, shutdown of air-handling systems, holding doors open and/or shut ). D-1.5 Evaluation of Enclosure Obtain or prepare a sketch plan showing the walls, the location of the door and other openings through w-hich air will flow during the test, and the location of any ducts penetrating the enclosure, and any dampers in the ducts. Show the status ( that is, whether open or closed when the extinguishant system is discharged ) of each door, hatch and damper, and which access opening(s) is (are) to be used for the fan unit. Show the location of floor and sink drains. D-1.6 Measurement of Enclosure during the test if this is needed to avoid temperature build-up in equipment such .as computers; and air-handling ii) Recirculating equipment which would continue to operate on extinguisharit discharge should be shut down, if it creates excessive bias pressure. 5) Post the appropriate [see D-1.2 (f) ]. signs on doors Measure the protected enclosure volume as necessary and record the following: a) b) c) Overall height of the protected enclosure, Height of the highest enclosure, and hazard in the 6-) Open doors and remove floor or ceiling tiles within the extinguishant- protected portions of the enclosure envelope so that the extinguishant- protected volume is treated as one space. Do not remove false ceiling tiles if the volume above the false ceiling is not protected with extinguishant. n 8) b) Close all doors and windows in the enclosure envelope. Check that liquid traps in the floor and sink drains are sealed with liquid. up Door Fan Unit Gross volume of the protected enclosure. Setting D-1.7 Test Procedure a) Preparation 1) for Test Advise supervisory area of the test. personnel in the 2) Remove papers and objects likely to be disturbed by the turbulence from the fan. Block open sufficient doors outside the enclosure envelope to provide an adequate return path for air between the fan unit and the enclosure leaks, while correcting any breach of any requirements of the facility, including requirements for security, fire protection and environmental boundaries. Using the sketch plan ( see D-1.5), set all air-handling equipment and extinguishant-extract ion systems to the state they would be in at the time of extinguishant system discharge, except for the following: i) Recirculating air-handling equipment without fresh air makeup which does not give a bias pressure across the enclosure boundary or otherwise preclude accurate testing, and which would be shut down on extinguishant discharge, may be left operating 23 1) Set up the fan unit in an access opening leading from the enclosure into the largest volume of building space which will complete the air-flow path from the fan, via the enclosure, leaks and building space back to the fan. 2) Gently blow into or suck from the flexible tubing so that the readings of the pressure-measuring devices traverse the full scale. Hold the maximum reading for not less than 10s. Release the pressure devices. 3) and zero the 3) 4) Connect the enclosure differential pressure-measuring device. Ensure that the open ends of the flexible tubing near the fan unit are away from its air stream path and any other air flows which might affect the readings. Use the fan(s) to raise or lower the pressure of the enclosure by approximately 15 Pa. Check all dampers with smoke and ensure that they are closing properly. Check doors and hatches and ensure correct closure, Inspect the wall perimeter ( above and below any false floor) and the floor slab for any major leaks and note their size and location. 4) 1S 15493:2004 C) A4easurement 1) of Bius Pressure Seal the fan unit inlet or outlet and, without the fan(s) operating, observe the enclosure differential pressure-measuring device for at least 30s. Ifa bias p~essure is indicated, use smoke to detect the consequent air flow and its direction. If the existence of a bias pressure is confirmed, record the pressure-measuring device reading as the bias pressure (Pb). If the enclosure is large, or if the bias pressure is largely caused by wind or stack effects, repeat the measurement at one or more different access openings. Record all the values measured and use the largest positive value ( or if only negative values are recorded, the value closest to zero ) as the bias pressure. or less evenly spaced over the range down to 10 Pa. 4) Use the fan unit to pressurize the enclosure and repeat the procedure of (d) (iii). Again record the value of ( Pf + Pb ), which will be positive. 2) NOTE -- For calculation purpose, either Pf or Pb or the average of the two can be taken. D-2 CALCULATIONS D-2.1 Notations 3) Q c P = air leakage rate, = flow coefficient; in m3/s; = pressure within enclosure, in Pa; N R~ = slope of the graph; = density of agent /air Mixture, in kg/m3; Agent Densi@, kg/m3 A bias pressure as low as 0.5 Pa can affect the accuracy of the test result. If the bias pressure has a numerical value greater than 25 percent of fire extinguishant/ air column pressure, then.the hold time is likely to be low and the enclosure may not hold the specified extinguishant concentration. The source of the excessive bias pressure should be identified and, if possible, permanently reduced. 10 the event of fluctuating bias pressures ( such as those created by wind effects), it may not be possible to achieve the necessary correlation accuracy in the fan test results. These fluctuating pressures may need to be eliminated before an accurate fan test can be carried out. d) Measurement 1) of Leakage Rate Air HCFC Blend A HFC-227ea IG-541 IG-55 RA R~ PM G= HO H= A= = density of air, in kg/m3; 1.202 3.84 7.26 1.41 1.41 = density of agent, in kg/m3; = agent/Air column pressure, in Pascal (Pa); gravitational acceleration, 9.81 m/s2; = total height of the enclosure, in m; Measure the air temperature inside the enclosure, Te, and measure the air temperature outside the enclosure TO, at several points. If the location of leaks is not known, use the average value; otherwise, use the average value weighed according to the known location of the leaks. Unseal the fan inlet or outlet and connect the fan flow pressure- measuring device. Use the fan unit to repressurize the enclosure to the maximum extent, but by not more than 60 Pa. Allow the differential pressure enclosure measuring reading to stabilize ( which may take up to 30s ) and record the value ( Pf+ Pb ) which will be negative. Repeat at not less than four more fan unit flow rates to give five readings more 24 minimum acceptable enclosure, in m; height in the area of the enclosure, in m2; volume of the enclosure, in m3; uncorrected agent/air mixture leakage rate, in m3/s; agent/air mixture leakage rate, in ins/s; v" ~= Q. = corrected TL T~ ELA K= 2) = temperature within the enclosure, in `C; = temperature outside the enclosure, in "C; = equivalent leakage area, in m2; 3) discharge coefficient ( 0.61 to I depending upon nature of leakage openings ); = total leakage area, in m2; = lower leak fraction; = area of lower leaks, in m2; . agent concentration, in percent; ILA LLF ALL c 1S 15493:2004 Cp = pass concentration in percent ( 80 perc~nt of the design agent concentration ); simplification constant; simplification constant; and agent/air mixtuFe leakage rate: QM= (Qm)(TL+z7s) M3,S (TP+273) C3 = equation C4 = equation T= retention time of pass concentration (CP) within the enclosure, in seconds. D-2.7 The next step will be todetermine the equivalent leakage area ( ELA ): ELA = D-2.8 (1.271 )(Q~) D-2.2 After pressurizing ( depressurizing ) the enclosure to various pressures, corresponding flow rates in 1/s for each room pressure shall be recorded wherefrom the flow at 1 Pa pressure i$ determined. This value (C) is deemed as flow coefficient ( constant ) for the purpose of calculation. The formula establishing a relation between flow and the pressure is Q = CPN where Q = Air leakage rate, in m3/s, C = Flow coefllcient, P = Pressure within enclosure in Pa and N = Slope of the graph. NOTE -- The value of N can be determined substituting by observed values for Q, P and C in the above v _ PM mz The next step will be to determine the total leakage area ( TLA ): TLA=(K)(ELA)m2 D-2.9 The next step will be to determine the lower leak fraction ( LLF): ALL LLF = -- TLA D-2.1 O The next step will be to determine the retention time ( T): T= (A)[(c3~o+c4) (1-h') equation. D-2.3 _(qf+c4)( I-iv)] s The next step will be to determine the density of agent/air mixture ( R~ ): RM= (RG)( c)+ (1-N) where (C3)(LLF)(TLA) (RA)(1OO-C) 100 100 kg/m3 C3 = C4 = the (2 G)(RM-RA) (R~)+(RA)[]flF D-2.4 The next step will be to determine the,agent/ air column pressure (PM): P~=(G)(HO) D-2.5 (R~­ RA)Pa 1 R~ l/N 2 ( Static pressure inside enclosure) The next step will be to determine uncorrected agent/air mixture leakage rate: NOTES 1 If static pressure is negative, then treat it as zero. -Qm=(c)(pM)Nm3/s D-2.6 The next step will be to determine the corrected 2 If static pressure value. is positive, then consider actual 25 IS 15493:2004 ANNEX E ( Clause 11.8.3 ) 1NFORMATION E-1 As the extinguishant the storage ON TWO-PHASE in FLOW FOR LIQUEFIED HALOCARBON GASES the liquid phase flows the pressure drops or recedes. The pressure recession varies with container fill density. It is assumed that there was thermodynamic equilibrium between the liquid and vapour phases in the storage container. In actual tests, it has been noted that there is a sharp drop in pressure during the initial rush of liquid into the distribution system. This is due to a lag between the pressure drop and the onset of boiling in the container. As boiling commences, the pressure returns to the pressures shown on the curves for respective gaseous extinguishants representing the calculated pressure in the storage container versus the percentage discharge of extinguishant from the container for both 2.5 MPa and 4.2 MPa systems. from container, Agent entering the distribution system is vaporized before it reaches the nozzles, due to heating by the pipe work and the initial low pressure in the system. The initial vaporization limits the flow of Agent through the distribution system because the mass flow of vapour is much lower than that ofliquid. E-6 LIQUID FLOW There is a significant delay between the opening of the discharge valve and the first appearance of liquid at the nozzles. Some of the delay is due to the flow restriction presented by the container and distribution system, however much of delay is due to the initial vapour phase flow of the Agent. E-7 PHASE SEPARATION The flow of Agent in the distribution system is a"twophase flow ( containing both liquid and vapour ). In a properly sized distribution system the flow will be highly turbulent throughout the system and the two phases will mix homogeneously. [fthe pipes are too big the phases may tend to separate, which can cause a variety of flow problems and can in some cases result in a reduced flow rate. E-8 AVERAGE PRESSURE CONDITIONS Pressure at the nozzle is not constant throughout discharge because the pressure in the storage container is constantly decreasing. If one were .to attempt manual calculation it would be desirable to use an average pressure condition. It is difficult to arrive at an average as the volume of piping has a marked effect on the average nozzle ( pressure, density and velocity conditions ), all of which, have a marked effect on discharge quantities and times. E-9 AVERAGE NOZZLE PRESSURE The nozzle pressure used for calculations is the pressure when half the liquid phase has been discharged from the nozzle. The timing of this is used to-calculate an average pressure drop in the distribution system. To calculate the correct storage container pressure, allowance must be made for the amount of liquid in the piping system. E-10 PERCENT IN DISTR1BUTION SYSTEM E-2 AGENT IN PIPE WORK Agent flows through the distribution system in both liquid and vapour phase. As the liquid phase flows through the distribution system the pressure continues to drop, causing the liquid to boil. The volume of the vapour phase increases with the decreasing pressure and hence the density of the mixture drops. To maintain a constant flow rate, the speed through the distribution system must continuously increase down the pipe work. The pressure drop for a given flow rate is no-tlinear, as it is with water, but is variable along the pipe. E-3 DENSITY -OF AGENT IN DISTRIBUTION SYSTEM Using the thermodynamic properties of the Agent, including the nitrogen used for superpressurization, the density of the two-phase mixture in the distribution system can be calculated. The density of the Agent leaving the storage container varies over the course of the discharge, The density is lowest at the start of discharge and increases until the last of the liquid leaves the container. E-4 TEMPERATURE The drop in container pressure as the Agent flows from the container causes remaining Agent in the container to cool. As a result, liquid that is below ambient temperature is introduced to the distribution system. During a system discharge the temperature of the Agent leaving the storage container recedes as a function of instantaneous container pressure. E-5 INITIAL VAPOUR TIME At the start of discharge virtually all the liquid phase 26 The points outlined above are taken into consideration to calculate the average container pressure during discharge. The ratio of the pipe volume to the volume of Agent supply expanded under flowing conditions varies with average container pressure, The former quantity shall be referred to as percent-in-the-pipe. -Bureau of Indian Standards BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote harmonious development of the activities of standardization, marking and quality certification of goods and attending to connected matters in the country. Copyright 131Shas the copyright of all its publications. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course of implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director (Publications), BIS. Review of Indian Standards Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of `BIS Catalogue' and `Standards : Monthly Additions'. This Indian Standard has been developed from Doc : No. Amendments Amend No. CED22(7011 ). 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